Methods and arrangements for frequency selective transmission

ABSTRACT

Logic may comprise hardware and/or code to select a narrow band from a wider channel bandwidth. Logic of communications between devices may select, e.g., a 1 or 2 MHz sub-channel from a wider channel bandwidth such as 4, 8, and 16 MHz and transmit packets on the selected 1 or 2 MHz channel. For instance, a first device may comprise an access point and a second device may comprise a station such as a low power sensor or a meter that may, e.g., operate on battery power. Logic of the devices may facilitate a frequency selective transmission scheme. Logic of the access point may transmit sounding packets or control frames across the sub-channels of the wide bandwidth channel, facilitating selection by the stations of a sub-channel and subsequent communications on the sub-channel between the access point and the station.

BACKGROUND

The present disclosure relates generally to the field of wirelesscommunications technologies. More particularly, the present disclosurerelates to frequency selective transmission communications.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts an embodiment of a wireless network comprising aplurality of communications devices, including multiple fixed or mobilecommunications devices;

FIG. 1A depicts an alternative embodiment of a wireless networkcomprising an access point (AP) and a station (STA);

FIG. 1B depicts an embodiment of a timing diagram for Frequencyselective transmission for restricted access window (RAW) based channelaccess;

FIG. 1C depicts an alternative embodiment of a timing diagram for asecond frequency selective transmission scheme for RAW based channelaccess;

FIG. 1D depicts an alternative embodiment of a timing diagram a thirdfrequency selective transmission scheme for target wake time (TWT) basedchannel access;

FIG. 1E depicts an alternative embodiment of a timing diagram a fourthfrequency selective transmission scheme for TWT based channel access;

FIG. 1F depicts an alternative embodiment of a timing diagram a fifthfrequency selective transmission scheme for TWT based channel access;

FIG. 1G depicts an alternative embodiment of a timing diagram a sixthfrequency selective transmission scheme for AP cycling (or hopping)across sub-channels periodically;

FIG. 1H depicts an embodiment of Sounding packets transmitted across allsub-channels simultaneously;

FIG. 1I depicts an alternative embodiment of Sounding packetstransmitted across all sub-channels sequentially;

FIG. 1J depicts an alternative embodiment of Sounding packetstransmitted across all sub-channels simultaneously multiple times;

FIG. 2 depicts an embodiment of an apparatus for frequency selectivetransmission;

FIGS. 3A-B depict embodiment of flowcharts for frequency selectivetransmission as discussed in conjunction with FIGS. 1-2; and

FIGS. 4A-C depict embodiment of flowcharts for frequency selectivetransmission as discussed in conjunction with FIGS. 1-2.

DETAILED DESCRIPTION OF EMBODIMENTS

The following is a detailed description of novel embodiments depicted inthe accompanying drawings. However, the amount of detail offered is notintended to limit anticipated variations of the described embodiments;on the contrary, the claims and detailed description are to cover allmodifications, equivalents, and alternatives as defined by the appendedclaims. The detailed descriptions below are designed to make suchembodiments understandable and obvious to a person having ordinary skillin the art.

Generally, embodiments for frequency selective transmissioncommunications are described herein. Embodiments may comprise logic suchas hardware and/or code to select a narrow band from a wider channelbandwidth. In some embodiments, communications between devices mayselect, e.g., a 1 or 2 MHz sub-channel from a wider channel bandwidthsuch as 4, 8, and 16 MHz and transmit packets on the selected 1 or 2 MHzchannel. In further embodiments, the 16 MHz channel bandwidth can besplit into two 8 MHz sub-channels or four 2 MHz sub-channels and, inother embodiments, the 8 MHz channel bandwidth can be split into two 4MHz channels. Embodiments are not limited to 1 or 2 MHz sub-channels. Insome embodiments, for instance, a first device may comprise an accesspoint and a second device may comprise a station such as a low powersensor or a meter that may, e.g., operate on battery power. In furtherembodiments, logic of the devices may facilitate a frequency selectivetransmission scheme. In several embodiments, the access point maytransmit sounding packets or control frames across the sub-channels ofthe wide bandwidth channel, facilitating selection by the stations of asub-channel and subsequent communications on the sub-channel between theaccess point and the station.

In some embodiments, the access point may implement a restricted accesswindow scheme in which devices are assigned to time slots for selectionof a sub-channel via a power saving poll or other trigger frame. Inother embodiments, the stations may implement a target wake time fordevices such as devices that wait much longer than beacon intervals towake to communicate with an access point. In still other embodiments,the access point may transmit a hopping schedule, which describes timeslots during which the access point will remain on each sub-channel, tothe stations in a beacon and then hop between each of the sub-channelsduring the beacon interval. Such embodiments allow the stations to hopbetween the sub-channels to determine whether communication quality onthe sub-channel is acceptable.

Various embodiments may be designed to address different technicalproblems associated with improving narrow channel bandwidthcommunications. For instance, some embodiments may be designed toaddress one or more technical problems such as increasing the number ofchannels with narrow channel bandwidths. The technical problem ofcoordinating the selection of channels with narrow channel bandwidths.

Different technical problems such as those discussed above may beaddressed by one or more different embodiments. For instance, someembodiments that are designed to address increasing the number ofchannels with narrow channel bandwidths may do so by one or moredifferent technical means such as sub-dividing a channel with a widerchannel bandwidth into multiple sub-channels. Further embodiments thatare designed to coordinate the selection of channels with narrow channelbandwidths may do so by one or more different technical means such asestablishing restricted access windows for selection of a sub-channel ofa wider channel bandwidth and communication via the sub-channels,establishing target wake times for devices that wait longer time periodsbetween communications, establishing a hopping schedule with time slotsduring which the access point may remain on a sub-channel for channelselection and communications, and/or the like. Further embodiments thatmay establish time slots within beacon intervals.

Some embodiments implement a one Megahertz (MHz) channel bandwidth forInstitute of Electrical and Electronic Engineers (IEEE) 802.11ahsystems. The lowest data rate in such embodiments may be approximately6.5 Megabits per second (Mbps) divided by 20=325 Kilobits per second(Kbps). If two times repetition coding is used, the lowest data ratedrops to 162.5 Kbps. In many embodiments, the lowest PHY rate is usedfor beacon and control frame transmissions. Many embodiments may enablesmall battery-powered wireless devices (e.g., sensors) to use Wi-Fi toconnect to the, e.g., Internet with very low power consumption.

Some embodiments may take advantage of Wireless Fidelity (Wi-Fi) networkubiquity, enabling new applications that often require very low powerconsumption, among other unique characteristics. Wi-Fi generally refersto devices that implement the IEEE 802.11-2007, IEEE Standard forInformation technology—Telecommunications and information exchangebetween systems—Local and metropolitan area networks—Specificrequirements—Part 11: Wireless LAN Medium Access Control (MAC) andPhysical Layer (PHY) Specifications(http://standards.ieee.org/getieee802/download/802.11-2007.pdf) andother related wireless standards.

Several embodiments comprise access points (APs) for and/or clientdevices of APs or stations (STAs) such as routers, switches, servers,workstations, netbooks, mobile devices (Laptop, Smart Phone, Tablet, andthe like), as well as sensors, meters, controls, instruments, monitors,appliances, and the like. Some embodiments may provide, e.g., indoorand/or outdoor “smart” grid and sensor services. For example, someembodiments may provide a metering station to collect data from sensorsthat meter the usage of electricity, water, gas, and/or other utilitiesfor a home or homes within a particular area and wirelessly transmit theusage of these services to a meter substation. Further embodiments maycollect data from sensors for home healthcare, clinics, or hospitals formonitoring healthcare related events and vital signs for patients suchas fall detection, pill bottle monitoring, weight monitoring, sleepapnea, blood sugar levels, heart rhythms, and the like. Embodimentsdesigned for such services generally require much lower data rates andmuch lower (ultra low) power consumption than devices provided in IEEE802.11n/ac systems.

Logic, modules, devices, and interfaces herein described may performfunctions that may be implemented in hardware and/or code. Hardwareand/or code may comprise software, firmware, microcode, processors,state machines, chipsets, or combinations thereof designed to accomplishthe functionality.

Embodiments may facilitate wireless communications. Some embodiments maycomprise low power wireless communications like Bluetooth®, wirelesslocal area networks (WLANs), wireless metropolitan area networks(WMANs), wireless personal area networks (WPAN), cellular networks,communications in networks, messaging systems, and smart-devices tofacilitate interaction between such devices. Furthermore, some wirelessembodiments may incorporate a single antenna while other embodiments mayemploy multiple antennas. The one or more antennas may couple with aprocessor and a radio to transmit and/or receive radio waves. Forinstance, multiple-input and multiple-output (MIMO) is the use of radiochannels carrying signals via multiple antennas at both the transmitterand receiver to improve communication performance.

While some of the specific embodiments described below will referencethe embodiments with specific configurations, those of skill in the artwill realize that embodiments of the present disclosure mayadvantageously be implemented with other configurations with similarissues or problems.

Turning now to FIG. 1, there is shown an embodiment of a wirelesscommunication system 1000. The wireless communication system 1000comprises a communications device 1010 that may be wire line andwirelessly connected to a network 1005. The communications device 1010may communicate wirelessly with a plurality of communication devices1030, 1050, and 1055 via the network 1005. The communications device1010 may comprise an access point. The communications device 1030 maycomprise a low power communications device such as a sensor, a consumerelectronics device, a personal mobile device, or the like. Andcommunications devices 1050 and 1055 may comprise sensors, stations,access points, hubs, switches, routers, computers, laptops, netbooks,cellular phones, smart phones, PDAs (Personal Digital Assistants), orother wireless-capable devices. Thus, communications devices may bemobile or fixed. For example, the communications device 1010 maycomprise a metering substation for water consumption within aneighborhood of homes. Each of the homes within the neighborhood maycomprise a sensor such as the communications device 1030 and thecommunications device 1030 may be integrated with or coupled to a watermeter usage meter.

The communications devices 1010, 1030, 1050, and 1055 may be capable ofone or more frequency selective transmission schemes or communicationsvia frequency selective transmission logic such as frequency selectivetransmission logic 1015 and 1035, and the frequency selectivetransmission logic 1015 of communications device 1010 may select one ormore frequency selective transmission protocols based upon capabilitiesdetermined about the communications devices 1030, 1050, and 1055 duringassociation with the communications device 1010. Various otherembodiments of frequency selective transmission protocols and componentsthereof implemented by frequency selective transmission logic such asfrequency selective transmission logic 1015 and 1035 are illustrated inFIGS. 1B-1J.

Initially, for example, the communications devices 1030, 1050, and 1055may receive a beacon from communications device 1010. In someembodiments, the beacon may comprise assignments for the communicationsdevices 1030, 1050, and 1055 of time slots to communicate withcommunications device 1010. The communications device 1010 may allocatea time slot for sounding. The sounding packets may be transmitted overall sub-channels of a wide channel bandwidth. For instance, a 4 MHzchannel may have two 2 MHz sub channels or four 1 MHz sub-channels. A 16MHz bandwidth may comprise four 4 MHz channels, eight 2 MHz channels orsixteen 1 MHz sub-channels.

The frequency selective transmission logic, such as the frequencyselective transmission logic 1035, of communications devices 1030, 1050,and 1055 may receive the sounding packets or control frames during thesounding period and the frequency selective transmission logic each ofthe communications devices 1030, 1050, and 1055 may select a sub-channelfor communications with communications device 1010.

In some embodiments, the frequency selective transmission logic of eachof the communications devices 1030, 1050, and 1055 may transmit apower-saving poll (PS-Poll) or other trigger frame during aPS-Poll/trigger phase in a first restricted access window (RAW1). Inresponse, the communications device 1010 may receive the PS-Poll orother trigger frames from the communications devices 1030, 1050, and1055 during RAW1. In some embodiments, the PS Polls or other triggerframes may comprise sub-channel indexes to indicate the particularsub-channel selected by the communications device. The frequencyselective transmission logic 1015 may record the selected sub-channelindexes in memory 1011 for each of the communications devices 1030,1050, and 1055.

During a data exchange phase (RAW2), the communications devices 1030,1050, and 1055 may communicate with the communications device 1010during their respective, assigned time slots. For instance, a framebuilder 1033 of communications device 1030 may generate or select aframe based upon a frame structure 1032 in memory 1031 of communicationsdevice 1030. The medium access control (MAC) sublayer logic 1038 maycommunicate with the physical layer (PHY) logic 1039 to transmit theframe to the PHY logic 1039 of communications device 1030.

In further embodiments, the communications devices 1030, 1050, and 1055may communicate with the communications device 1010 on the selectedsub-channel and such communication may inform the communications device1010 of the selected sub-channel for communications by the particularcommunications device at least for the particular beacon interval.

FIG. 1A illustrates an alternative embodiment of a wireless network 1090comprising an access point (AP1) and a station (STA1). In thisembodiment, the AP1 may comprise a high-powered communications deviceand the STA1 may comprise battery-powered sensor or meter that collectsdata and wakes periodically to transmit the data to the AP1. In thepresent embodiment, the AP1 may establish a frequency selectivetransmission protocol with the STA1 based upon the capabilities of theSTA1. In particular, the STA1 may be capable of receiving a narrowbandwidth communication. In such embodiments, the AP1 may establish asounding duration to transmit sounding packets transmitted across allsub-channels sequentially to facilitate selection of the sub-channel bythe STA1. In other embodiments, the STA1 may be capable of receivingwideband transmissions and the AP1 may transmit all the sounding packetstransmitted across all sub-channels simultaneously. In furtherembodiments, the AP1 may transmit all the sounding packets transmittedacross all sub-channels simultaneously multiple times.

FIG. 1B depicts an embodiment of a timing diagram 1100 for frequencyselective transmission for reserved access window (RAW) based channelaccess. In this embodiment, the AP may assign time slots to STAs througha beacon 1112 transmitted on a primary channel (C1) 1110 for, e.g., twoRAWs. The AP may allocate the first RAW (RAW1 1120) for sub-channelselection and, in some embodiments, may be referred to as thePS-Poll/trigger phase. The AP may allocate the second RAW phase (RAW21130) for data exchange between the AP and the STAs and this phase maybe referred to as the data exchange phase.

With the beacon 1112, the AP may also allocate a time slot for asounding period 1114. The time slot for the sounding period may bereserved for a time duration of T to facilitate receipt of the soundingpackets 1116 by the STAs. The AP may send the sounding packets 1116 overall sub-channels (e.g., four 2 MHz channels in the present embodiment)at the same time or sequentially. The STAs may receive the soundingpackets 1116 during the sounding period 1114 and each STA may choose asub-channel (C1, C2, C3 or C4). The STAs can receive the soundingpackets 1116 across all sub-channels (C1, C2, C3 and C4) sequentially byswitching between the sub-channels (C1, C2, C3 and C4) or, if the APtransmits the sounding packets 1116 simultaneously such as isillustrated in FIG. 1H or 1I, the STAs may be capable of receiving thesounding packets 1116 across all sub-channels at the same time.

After transmitting the beacon 1112 with the time slot allocations forthe RAW1 1120 and RAW2 1130, each STA may communicate with the AP duringthe time slot assigned to the STA during each of the phases 1120 and1130. The time slot assignments in the present embodiments are demarkedin FIG. 1B by the STA number above each time slot such as STA1, STA2through STAn for N stations. STAn denotes the Nth station.

Each STA may signal the sub-channel that the STA selected in a PS-Pollor trigger frame during the PS-Poll/trigger phase, RAW1 1120. Someembodiments, may, for instance, assume that the AP and the STAs cancommunicate on the primary sub-channel (C1) 1110 at the lowestmodulation and coding scheme (MCS) transmission rate. The PS-Poll orother trigger frame may signal the selected sub-channel index with 2-4bits in a field of the PS-Poll assuming a sub-channel is selected from atotal of 4 to 16 sub-channels.

In many embodiments, the AP responds to the STAs PS-Poll with anacknowledgement frame on the primary sub-channel C1 1120. In the presentembodiment, the STA1 transmits a PS-Poll to the AP during the RAW1 1120with a sub-channel index indicating sub-channel C1, the STA2 transmits aPS-Poll to the AP during the RAW1 1120 with a sub-channel indexindicating sub-channel C3, and the STAn transmits a PS-Poll to the APduring the RAW1 1120 with a sub-channel index indicating sub-channel C4.The AP may acknowledge the selection by responding with theacknowledgement within the time slots of RAW1 1120 for STA1, STA2, andSTAn, respectively.

The AP records the selected sub-channel index for each STA and uses thatselected sub-channel for data exchanges during the correspondingassigned time slots in the data exchange phase, RAW2 1130. For instance,the STA1 transmits two data packets during the time slot for STA1 andreceives an ACK transmitted from the AP after each data packettransmission. The sounding period may represent an additional overheadfor this frequency selective transmission protocol.

In further embodiments, the communications device 1010 may facilitatedata offloading. For example, communications devices that are low powersensors may include a data offloading scheme to, e.g., communicate viaWi-Fi, another communications device, a cellular network, or the likefor the purposes of reducing power consumption consumed in waiting foraccess to, e.g., a metering station and/or increasing availability ofbandwidth. Communications devices that receive data from sensors such asmetering stations may include a data offloading scheme to, e.g.,communicate via Wi-Fi, another communications device, a cellularnetwork, or the like for the purposes of reducing congestion of thenetwork 1005.

The network 1005 may represent an interconnection of a number ofnetworks. For instance, the network 1005 may couple with a wide areanetwork such as the Internet or an intranet and may interconnect localdevices wired or wirelessly interconnected via one or more hubs,routers, or switches. In the present embodiment, network 1005communicatively couples communications devices 1010, 1030, 1050, and1055.

The communication devices 1010 and 1030 comprise memory 1011 and 1031,and MAC sublayer logic 1018 and 1038, respectively. The memory 1011 and1031 may comprise a storage medium such as Dynamic Random Access Memory(DRAM), read only memory (ROM), buffers, registers, cache, flash memory,hard disk drives, solid-state drives, or the like. The memory 1011 and1031 may store the frames and/or the frame structures such as standardframe structures identified in IEEE 802.11.

FIG. 1C illustrates an alternative embodiment of a timing diagram 1150for a second frequency selective transmission scheme for reserved accesswindow (RAW) based channel access. In the present embodiment, the AP maytransmit a beacon 1162 to reserve a sounding period 1164 to transmitsounding packets 1166, reserve a time duration (T) for thePS-Poll/trigger phase, RAW1 1170, and assign time slots to the STAs(STA1, STA2, through STAn) for the data exchange phase, RAW2 1180.

Each STA may select a sub-channel (e.g., the best sub-channel in termsof signal to noise, signal strength, and/or other) and transmit aPS-Poll or other trigger frame on that sub-channel to identify theselected sub-channel. The STA may not need to signal the selectedsub-channel index in the PS-Poll/trigger frame such as by a sub-channelindex because the AP can determine the selected sub-channel by receivingthe PS-Poll/trigger frame on the selected sub-channel. For instance, theSTA2 may receive the sounding packets on all the sub-channels (C1, C2,C3, and C4), determine that sub-channel C3 offered the bestcommunication characteristics, and transmit a PS-Poll frame to the AP onsub-channel C3 in the time slot for STA2 during the RAW1 1170.

The AP may record the selected sub-channel index for each STA in memorysuch as memory 1011 in FIG. 1 and may use that sub-channel for dataexchanges (D denotes data packet and A denotes ACK in FIG. 1B) duringthe assigned time slot in the data exchange phase (RAW2). For instance,the STA2 selects the sub-channel C3 during RAW1 and, during RAW2 1180,the STA2 transmits data during the time slot allocated to STA2 in theRAW2 1130. The AP may respond to each data packet from the STAs with anACK.

In several embodiments, the AP is capable of decoding a packet receivedon any sub-channel so that the AP can identify the sub-channels selectedby the STAs based upon the sub-channel on which the STAs communicate. Insuch embodiments, the AP may be more capable in some respects than theAP illustrated in FIG. 1B.

FIG. 1D illustrates an alternative embodiment of a timing diagram athird frequency selective transmission scheme for target wake time (TWT)based channel access. The TWT based channel access may operateseparately or in conjunction with the other embodiments describedherein. In the present embodiment, the AP may transmit shortclear-to-send (CTS) frames (Synch frames) across all the sub-channels(C1, C2, C3, and C4) either simultaneously or sequentially. All thesub-channels (C1, C2, C3, and C4) may be reserved for a time duration T,which may be a maximum transmission operation (TXOP) or an estimateddata transmission time, to prevent possible hidden node problems untilthe end of the packet transactions.

The TWT 1215 illustrated may be the TWT for STAn. In other words, duringassociation or during a beacon transmission (not shown), the AP may haveassigned the TWT to STAn and the STAn may wake to receive the short CTS.The STAn may select a sub-channel C3 and send a data packet on theselected sub-channel. The AP may detect the transmission on sub-channelC3, identifying the selected sub-channel, and may decode the data packetreceived on the sub-channel C3. The unselected sub-channels during T maynot be used because they are reserved by a network allocation vector(NAV) 1225 through the entire exchange (Data denotes data packet and Adenotes ACK in FIG. 1D).

FIG. 1E illustrates an alternative embodiment of a timing diagram 1300that is a fourth frequency selective transmission scheme and the schemeimplements TWT based channel access. In the present embodiment, the APmay send sounding frames across all sub-channels either simultaneouslyor sequentially. Note that the illustrations include simultaneoussounding packets but other embodiments include other sounding packetarrangements such as those illustrated in FIG. 1H-J.

The AP may transmit sounding frames 1320 to a STAn at the TWT of theSTAn. The sounding packets may comprise a receiver address (RA) of STAn,a transmitter address (TA) of the AP, and a NAV duration that providessufficient time for the STAn to respond with an RTS. All thesub-channels (C1, C2, C3, and C4) may be reserved by the NAV 1325 toallow the STAn to select any of the sub-channels (C1, C2, C3, and C4).

The STAn may select the sub-channel C3 based upon characteristics of thesub-channels. Upon selecting the sub-channel C3, the STAn may transmitthe RTS frame to the AP on the sub-channel C3 to identify thesub-channel C3 as the selected sub-channel and to set the NAV for thesub-channel C3 only for the remainder of the data exchange 1330. The APmay respond to the RTS with a CTS and the data exchange (D denotes datapacket and A denotes ACK in FIG. 1E) may proceed thereafter.

In many embodiments, the STAn may open its reception (RX) chain only forthe selected sub-channel only. The AP may also open its RX chain onlyfor the selected sub-channel. In such embodiments, the unselectedsub-channels (C1, C2, and C4) can be used by Optimal Base StationScheduler (OBSS) STAs after the end of the RTS frame.

FIG. 1F illustrates an alternative embodiment of a timing diagram 1400 afifth frequency selective transmission scheme and the scheme mayimplement TWT based channel access. In the present embodiment, the APmay send sounding frames 1420 across all sub-channels (C1, C2, C3, andC4) either simultaneously or sequentially. Note that many embodimentsherein describe four sub-channels (C1, C2, C3, and C4) for illustrativepurpose to clearly show compare the various embodiments, however,embodiments may comprise any number of sub-channels. The number ofsub-channels in a channel with a wide channel bandwidth may be up to thewide channel bandwidth divided by the narrow channel bandwidth.

The AP may send sounding frames to a STAn at the TWT of the STAn and thesounding frames may include a NAV of a duration to reserve all thesub-channels (C1, C2, C3, and C4) for a PS-Poll/trigger frame from theSTAn, an ACK (A denotes ACK in FIG. 1F) or a response frame from the AP,and an RTS from the STAn as shown in FIG. 1F. All the sub-channels maybe reserved during this period of time to protect transmissions fromother STAs.

The STAn may respond with the PS-Poll on the primary sub-channel 1410and the AP may respond with an ACK or response frame on the primarysub-channel 1410. In such embodiments, the ACK or response frame maycontain the selected sub-channel index. The STAn may select thesub-channel C3 based on the sounding frames 1420 and send an RTS on theselected sub-channel C3. The RTS may set other STAs' NAV on the selectedsub-channel C3 and the STA may open its RX chain only for the selectedsub-channel C3, potentially facilitating use of the unselectedsub-channels.

In response to the RTS from the STAn, the AP may transmit a CTS on theselected channel C3 and open its RX chain only for the selectedsub-channel C3. Thereafter, the AP and the STA may exchange Data and ACKframes on the selected channel C3. And the unselected sub-channels (C1,C2, and C4) can be used by OBSS STAs after transmission of the RTSframe.

FIG. 1G illustrates an alternative embodiment of a timing diagram 1500 asixth frequency selective transmission scheme that implements AP cycling(or hopping) across sub-channels periodically. In the presentembodiment, the AP may cycle through N sub-channels (e.g., C1, C2, C3,and C4) periodically. The AP may transmit a beacon at each beaconinterval that may contain the AP's sub-channel ‘hopping’ schedule (e.g.,when and how long the AP will stay on each sub-channel) and hoppingschedules of OBSSs may be coordinated to better utilize sub-channels(C1, C2, C3, and C4). FIG. 1G illustrates a single beacon interval 1515.

The AP may transmit beacons demarking the beacon intervals on theprimary sub-channel C1 1510. In some embodiments, a sounding period 1520may follow a beacon or, in further embodiments, the sounding period isnot included in the beacon interval and the AP, instead, transmitsbeacons as sounding packets on each of the sub-channels (C1, C2, C3, andC4) at the beginning of each time slot allocated for the AP to remain onthe sub-channel in accordance with the hopping schedule.

A STA may estimate channel quality of each sub-channel during thesounding period or based on the beacons (B) transmitted on each of thesub-channels (C1, C2, C3, and C4). When using beacons for channelestimation, after receiving a beacon on a sub-channel and if the STAdetermines that the channel quality is good enough to use based on thereceived beacon, the STA may decide to stay on that sub-channel andaccess the channel. Otherwise, the STA may move on to the nextsub-channel on which the AP is scheduled to stay for a durationindicated in the hopping schedule.

The STA may select a sub-channel and access the sub-channel when the APis on that sub-channel. And the AP may adjust time durations (e.g. TC1,TC2, TC3, and TC4 in FIG. 1G) independently from each other based on thetraffic loads of the sub-channels (C1, C2, C3, and C4).

FIGS. 1H-1J may illustrate different sounding options for the variousfrequency selective transmission schemes. FIG. 1H depicts an embodiment1600 of sounding packets transmitted across all sub-channels (C1, C2,C3, and C4) simultaneously during the sounding period. In someembodiments, this scheme offers short sound duration. In furtherembodiments, the STA has to be capable to receive much wider bandwidththan it is actually using for transmission and reception (TX/RX).

FIG. 1I depicts an alternative embodiment 1700 of sounding packetstransmitted across all sub-channels (C1, C2, C3, and C4) sequentiallyduring a sounding period. In some embodiments, this scheme works withSTAs without capabilities for a wider channel bandwidth than it needsfor TX/RX. In further embodiments, the sounding period may be longer andthe sounding packet may not be transmitted in time if one of thesub-channels becomes occupied by other packet transmissions. In otherwords, the interference patterns may change across the duration of along sounding period.

FIG. 1J depicts an alternative embodiment 1800 of sounding packetstransmitted across all sub-channels C1, C2, C3, and C4) simultaneouslyand repeatedly, multiple times. In some embodiments, this scheme allowsSTAs to choose whether to receive the sounding packets simultaneously orsequentially. In further embodiments, there may be no disruptions fromother STAs transmissions because the sounding packets are utilizing allthe sub-channels throughout the sounding period.

Referring again to FIG. 1, the MAC sublayer logic 1018, 1038 maycomprise logic to implement functionality of the MAC sublayer of thedata link layer of the communications device 1010, 1030. The MACsublayer logic 1018, 1038 may generate the frames such as managementframes, data frames, and control frames, and may communicate with thePHY logic 1019, 1039 to transmit the frames. The PHY logic 1019, 1039may generate physical layer protocol data units (PPDUs) based upon theframes. More specifically, the frame builders 1013 and 1033 may generatethe frames and data unit builders of the PHY logic 1019, 1039 mayencapsulate the frames with preambles to generate PPDUs for transmissionvia a physical layer device such as the transceivers (RX/TX) 1020 and1040.

The frame, also referred to as a MAC layer Service Data Unit (MSDU), maycomprise a control frame or a management frame. For example, framebuilder 1013 may generate a management frame such as the beacon frame toidentify the communications device 1010 as having capabilities such assupported data rates, privacy settings, quality of service support(QoS), power saving features, cross-support, and a service setidentification (SSID) of the network to identify the network to thecommunications device 1030. For instance, the communications devices1010, 1030, 1050, and 1055 may be compliant with IEEE 802.11ah, whichsupports mandatory 1 MHz and 2 MHz channel bandwidths and optional 4MHz, 8 MHz, and 16 MHz channel bandwidths. Although a much narrowerchannel bandwidth improves receiver sensitivity by 10-20 times comparedto 20 MHz channel bandwidth of 802.11 in 2.4 GHz and 5 GHz bands, 1 or 2MHz signal transmissions may experience high multipath fading loss dueto much reduced frequency diversity compared to 20 MHz signaltransmissions. Thus, in many embodiments, a management frame such as abeacon or an association response frame may indicate that thecommunications device 1010 is capable of one or more frequency selectivetransmission schemes that may attenuate the loss by utilizing the narrowband sub-channels within the wide bandwidth channels such as 1 MHz or 2MHz sub-channels.

The communications devices 1010, 1030, 1050, and 1055 may each comprisea transceiver such as transceivers 1020 and 1040. Each transceiver 1020,1040 comprises a radio 1023, 1043 comprising an RF transmitter and an RFreceiver. Each RF transmitter impresses digital data onto an RFfrequency for transmission of the data by electromagnetic radiation. AnRF receiver receives electromagnetic energy at an RF frequency andextracts the digital data therefrom.

FIG. 1 may depict a number of different embodiments including aMultiple-Input, Multiple-Output (MIMO) system with, e.g., four spatialstreams, and may depict degenerate systems in which one or more of thecommunications devices 1010, 1030, 1050, and 1055 comprise a receiverand/or a transmitter with a single antenna including a Single-Input,Single Output (SISO) system, a Single-Input, Multiple Output (SIMO)system, and a Multiple-Input, Single Output (MISO) system.

In many embodiments, transceivers 1020 and 1040 implement orthogonalfrequency-division multiplexing (OFDM). OFDM is a method of encodingdigital data on multiple carrier frequencies. OFDM is afrequency-division multiplexing scheme used as a digital multi-carriermodulation method. A large number of closely spaced orthogonalsub-carrier signals are used to carry data. The data is divided intoseveral parallel data streams or channels, one for each sub-carrier.Each sub-carrier is modulated with a modulation scheme at a low symbolrate, maintaining total data rates similar to conventionalsingle-carrier modulation schemes in the same bandwidth.

An OFDM system uses several carriers, or “tones,” for functionsincluding data, pilot, guard, and nulling. Data tones are used totransfer information between the transmitter and receiver via one of thechannels. Pilot tones are used to maintain the channels, and may provideinformation about time/frequency and channel tracking. Guard intervalmay be inserted between symbols such as the short training field (STF)and long training field (LTF) symbols during transmission to avoidinter-symbol interference (ISI), which might result from multi-pathdistortion. Guard tones help the signal conform to a spectral mask. Thenulling of the direct component (DC) may be used to simplify directconversion receiver designs.

In some embodiments, the communications device 1010 optionally comprisesa Digital Beam Former (DBF) 1022, as indicated by the dashed lines. TheDBF 1022 transforms information signals into signals to be applied viathe radio 1023, 1043 to elements of an antenna array 1024. The antennaarray 1024 is an array of individual, separately excitable antennaelements. The signals applied to the elements of the antenna array 1024cause the antenna array 1024 to radiate one to four spatial channels.Each spatial channel so formed may carry information to one or more ofthe communications devices 1030, 1050, and 1055. Similarly, thecommunications device 1030 comprises a transceiver 1040 to receive andtransmit signals from and to the communications device 1010. Thetransceiver 1040 may comprise an antenna array 1044 and, optionally, aDBF 1042.

FIG. 2 depicts an embodiment of an apparatus to generate, communicate,transmit, receive, communicate, and interpret a frame. The apparatuscomprises a transceiver 200 coupled with medium access control (MAC)sublayer logic 201. The MAC sublayer logic 201 may determine a framesuch as an association request frame, an association response frame, ora beacon frame, and transmit the frame to the physical layer (PHY) logic250. The PHY logic 250 may determine the PPDU by determining a preambleand encapsulating the frame with a preamble to transmit via transceiver200.

In many embodiments, the MAC sublayer logic 201 may comprise a framebuilder 202 to generate frames (MPDUs). For embodiments such ascommunications devices that associate with an access point, the MACsublayer logic 201 may generate an association request that includesfields descriptive of capabilities of the communications device. The MACsublayer logic 201 may then receive and parse and interpret anassociation response frame to determine the slot times defined for thecommunications device. For embodiments such as access points, the MACsublayer logic 201 may comprise a frame builder 202 to generate anassociation response frame to define slot times, RAWs, TWTs, hoppingschedules, or the like for communications between other communicationsdevices and the access point.

The PHY logic 250 may comprise a data unit builder 203. The data unitbuilder 203 may determine a preamble and the PHY logic 250 mayencapsulate the MPDU with the preamble to generate a PPDU. In manyembodiments, the data unit builder 203 may create the preamble basedupon communications parameters chosen through interaction with adestination communications device.

The transceiver 200 comprises a receiver 204 and a transmitter 206. Thetransmitter 206 may comprise one or more of an encoder 208, a modulator210, an OFDM 212, and a DBF 214. The encoder 208 of transmitter 206receives and encodes data destined for transmission from the MACsublayer logic 202 with, e.g., a binary convolutional coding (BCC), alow density parity check coding (LDPC), and/or the like. The modulator210 may receive data from encoder 208 and may impress the received datablocks onto a sinusoid of a selected frequency via, e.g., mapping thedata blocks into a corresponding set of discrete amplitudes of thesinusoid, or a set of discrete phases of the sinusoid, or a set ofdiscrete frequency shifts relative to the frequency of the sinusoid. Theoutput of modulator 210 is fed to an orthogonal frequency divisionmultiplexer (OFDM) 212, which impresses the modulated data frommodulator 210 onto a plurality of orthogonal sub-carriers. And, theoutput of the OFDM 212 may be fed to the digital beam former (DBF) 214to form a plurality of spatial channels and steer each spatial channelindependently to maximize the signal power transmitted to and receivedfrom each of a plurality of user terminals.

The transceiver 200 may also comprise duplexers 216 connected to antennaarray 218. Thus, in this embodiment, a single antenna array is used forboth transmission and reception. When transmitting, the signal passesthrough duplexers 216 and drives the antenna with the up-convertedinformation-bearing signal. During transmission, the duplexers 216prevent the signals to be transmitted from entering receiver 204. Whenreceiving, information bearing signals received by the antenna arraypass through duplexers 216 to deliver the signal from the antenna arrayto receiver 204. The diplexers 216 then prevent the received signalsfrom entering transmitter 206. Thus, duplexers 216 operate as switchesto alternately connect the antenna array elements to the receiver 204and the transmitter 206.

The antenna array 218 radiates the information bearing signals into atime-varying, spatial distribution of electromagnetic energy that can bereceived by an antenna of a receiver. The receiver can then extract theinformation of the received signal.

The transceiver 200 may comprise a receiver 204 for receiving,demodulating, and decoding information bearing signals. The receiver 204may comprise one or more of a DBF 220, an OFDM 222, a demodulator 224and a decoder 226. The received signals are fed from antenna elements218 to a Digital Beam Former (DBF) 220. The DBF 220 transforms N antennasignals into L information signals. The output of the DBF 220 is fed tothe OFDM 222. The OFDM 222 extracts signal information from theplurality of subcarriers onto which information-bearing signals aremodulated. The demodulator 224 demodulates the received signal,extracting information content from the received signal to produce anun-demodulated information signal. And, the decoder 226 decodes thereceived data from the demodulator 224 and transmits the decodedinformation, the MPDU, to the MAC sublayer logic 201.

After receiving a frame, the MAC sublayer logic 201 may access framestructures in memory to parse the frame to determine, e.g., whether theaccess point is buffering data for the communications device, the bitposition of the bit, the beacon sequence number, and/or the like. Basedupon this information, the MAC sublayer logic 201 may determine a slottime for communicating with an access point. The MAC sublayer logic 201may communicate with the access point by transmitting a trigger frame totrigger the access point to transmit the data being buffered for thecommunications device by the access point to the communications device.In several embodiments, the MAC sublayer logic 201 may implementfrequency select transmission logic such as the frequency selecttransmission logic 1015 and 1035 described in conjunction with FIGS. 1and 1A-1J.

Persons of skill in the art will recognize that a transceiver maycomprise numerous additional functions not shown in FIG. 2 and that thereceiver 204 and transmitter 206 can be distinct devices rather thanbeing packaged as one transceiver. For instance, embodiments of atransceiver may comprise a Dynamic Random Access Memory (DRAM), areference oscillator, filtering circuitry, synchronization circuitry, aninterleaver and a deinterleaver, possibly multiple frequency conversionstages and multiple amplification stages, etc. Further, some of thefunctions shown in FIG. 2 may be integrated. For example, digital beamforming may be integrated with orthogonal frequency divisionmultiplexing. In some embodiments, for instance, the transceiver 200 maycomprise one or more processors and memory including code to performfunctions of the transmitter 206 and/or receiver 204.

FIGS. 3A-B depicts an embodiment of a flowchart 300 for frequencyselective transmission as discussed in conjunction with FIGS. 1-2. Inparticular, FIG. 3A describes a process of frequency selectivetransmission by an AP. The flowchart 300 begins with transmittingpackets wirelessly on sub-channels of a wide bandwidth channel (element305). In many embodiments, transmitting the packets comprisestransmitting sounding packets across all of the sub-channels of the widebandwidth channel during a sounding period. In some embodiments,transmitting the packets comprises transmitting synch frames across thesub-channels during a sounding period. In further embodiments,transmitting the packets comprises transmitting the beacons.

After transmitting the packets, the AP may receive a selection of asub-channel from a receiving communications device (element 310). Insome embodiments, receiving a selection comprises receiving a powersaving poll or other trigger frame. In further embodiments, receiving aselection comprises receiving a communication from the communicationsdevice via the selected sub-channel.

After receiving the selection of the sub-channel, the AP may communicatewith the receiving communications device via the sub-channel (element315). For instance, the STA may transmit a data frame during a dataphase of a RAW and the AP may respond with an ACK. In furtherembodiments, the STA may transmit a ready-to-send (RTS) frame, the APmay respond with a clear-to-send (CTS) frame, and then the STA maytransmit data to the AP. In another embodiment, all the sub-channels maybe reserved for the data exchange time slot and the STA may transmit oneor more data frames to the AP within the time slot.

FIG. 3B describes a process of frequency selective transmission by a STAassociated with an AP. The flowchart 300 begins with receiving packetswirelessly on sub-channels of a wide bandwidth channel (element 355). Insome embodiments, the AP may transmit the packets simultaneously,multiple times in succession during a sounding period. In suchembodiments, the STA may receive the packets either simultaneously orsequentially by changing sub-channels between receipt of each of thepackets. In several embodiments, the determination regarding whether toreceive the packets simultaneously or sequentially may be based uponreceiver capabilities or may be based upon the power consumption ofreceiving the packets sequentially versus the power consumption ofreceiving the packets simultaneously.

After receiving the packets, the STA may transmit a selection of asub-channel to the AP (element 360). In several embodiments, the STA maytransmit the selection of the sub-channel to the AP on the primarysub-channel or a default sub-channel for communications with the AP. Insuch embodiments, the STA may transmit a frame such as a PS-Poll frameto the AP and the PS-Poll frame may comprise an index for the selectedsub-channel to identify the selected sub-channel to the AP. In furtherembodiments, the STA may transmit a frame on the selected sub-channeland the AP can determine the selected cub-channel based upon receipt ofthe frame rather than parsing the frame to determine the index.

The STA may communicate with the AP via the sub-channel (element 365).In some embodiments, the process of identifying the sub-channel to theAP and communicating, e.g., a data frame to the AP occurs at the sametime. In other words, the communication of a frame such as the dataframe on the selected sub-channel serves as the identification of thesub-channel to the AP.

FIGS. 4A-C depicts an embodiment of a flowchart for frequency selectivetransmission as discussed in conjunction with FIGS. 1-2. In particular,FIG. 4A depicts a flowchart 400 of a restricted access window (RAW)embodiment. The flowchart 400 begins with the AP assigning time slots tothe STAs through transmission of a beacon (element 405). The flowchart400 may describe the actions occurring during a beacon interval, whichmay be the time interval between transmissions of beacons by the AP tothe associated STAs. In many embodiments, the AP may utilize the beaconsto reserve a time duration (T) for the PS-Poll/trigger phase and eachSTA may transmit a PS-Poll to the AP during their assigned time slotwithin the Poll/trigger phase. In several embodiments, the AP mayutilize the beacons to transmit assignments for time slots during thedata exchange phase of the beacon interval to the STAs.

The AP may then allocate a time slot for sounding period and transmitsounding packets over all sub-channels (e.g. eight 2 MHz channels of a16 MHz bandwidth channel) (element 410). In several embodiments, thesounding packets may be transmitted simultaneously on all sub-channelsduring the sounding period and, in some of these embodiments, thesounding packets may be transmitted across all sub-channelssimultaneously multiple times so the STAs can choose whether to receivethe sounding packets frames sequentially or simultaneously. In otherembodiments, the sounding packets may be transmitted sequentially on allsub-channels of the bandwidth.

After the AP transmits the sounding packets, the STAs may receive thesounding packets during the sounding period and each STA may choose asub-channel (element 415). The STAs can receive the sounding packetsacross all sub-channels either at the same time or sequentially byswitching channels after receipt of each of the sounding packets. Whilereceiving the all the sounding packets simultaneously reduces thesounding period or duration, receiving the packets simultaneouslyrequires the STA to have the capability of receiving wide bandwidthcommunications.

Upon receipt of the sounding packets, each STA may choose thesub-channel based upon a determination as to the best sub-channel forcommunications. For instance, the STAs may choose a sub-channel basedupon the signal-to-noise ratio associated with each channel and/or othercriteria.

After selecting a sub-channel, each STA signals the selected sub-channelin a PS-Poll or trigger frame during the PS-Poll/trigger phase of theRAW (element 420). In many embodiments, the STA and the AP cancommunicate on the primary channel at, e.g., the lowest modulation andcoding scheme (MCS) transmission rate for the basic service set. Theselected channel index can be signaled by 2-4 bits assuming asub-channel is selected from 4-16 sub-channels. The AP records theselected sub-channel index for each STA and uses that sub-channel fordata exchanges with the STA during the assigned time slot for the STA inthe data exchange phase of the RAW.

In other embodiments, the STA selects its best sub-channel and transmitsa PS-Poll/trigger frame on that sub-channel. In such embodiments, theSTA may not need to signal the selected sub-channel index in thePS-Poll/trigger frame because the AP can determine the selectedsub-channel based upon the sub-channel on which the AP received thePS-Poll/trigger frame. Furthermore, in such embodiments, the AP has tobe capable of decoding a packet received on any of the sub-channels.

The STA may then communicate with the AP via the sub-channel (element425). For instance, the STA may transfer sensor data collected by theSTA to the AP during the time slot assigned to the STA and over thesub-channel selected by the STA. Note that the selection of thesub-channel may change between different beacon intervals because theSTA may select different sub-channels depending upon, e.g., the priorinterference patterns associated with communications over thesub-channel from the previous beacon interval during which the STAcommunicated with the AP.

FIG. 4B depicts a flowchart 400 of a target wake time (TWT) embodiment.The TWT may be a wake time assigned or otherwise associated with astation that is known to the AP. The AP may send packets to a STA andreserve all the sub-channels (element 435). In some embodiments, APsends control frames such as Short CTS frames (or Synch frames) acrossall sub-channels either simultaneously or sequentially. All thesub-channels may be reserved for a time duration T to prevent possiblehidden node problem until the end of the packet transactions. The timeduration T may be, e.g., a maximum transmission operation (TXOP) timeduration or an estimated data transmission time duration.

In further embodiments, the AP transmits sounding frames across allsub-channels either simultaneously or sequentially. AP sends soundingframes to a STA at the TWT of the STA. All the sub-channels are reservedthrough receipt of an RTS frame from the STA to protect transmissionsfrom other STAs. In some embodiments, the RTS frame from the STA may seta network allocation vector (NAV) on the selected sub-channel such thatthe selected sub-channel is reserved through the end of the packettransmissions between the STA and the AP.

In other embodiments, AP sends sounding frames across all sub-channelsto a STA at the TWT of the STA. All the sub-channels are reservedawaiting receipt of a PS-Poll/trigger frame from the STA, an ACK or aresponse frame from the AP, and an RTS from the STA. All thesub-channels are reserved during this period of time to protecttransmissions from other STAs.

In response, the STA may select a sub-channel (element 440). In severalembodiments, the STA selects a sub-channel based on the sounding frames,the control frames, and determinations related to the quality of thesub-channel for the purposes of communications between the STA and theAP.

The STA may then communicate the selection and communicate on theselected sub-channel with the AP (element 445). In some embodiments, theAP is capable of decoding a packet received on any sub-channel and theunselected sub-channels during T are wasted. In many embodiments, theSTA sends an RTS on the selected sub-channel. The RTS may set the NAV ofother STAs on the selected sub-channel. After transmitting the RTS, theSTA may open its receive (RX) chain only for the selected sub-channel.The AP may reply with a CTS on the selected sub-channel. And the APopens its RX chain only for the selected sub-channel.

Once the RTS and CTS are transmitted, the AP and the STA may exchangeData frames and ACK frames on the selected sub-channel. The unselectedsub-channels can be used by Optimal Base Station Scheduler (OBSS) STAsafter the end of the RTS frame transmitted by the STA.

In further embodiments, PS-Poll and the response frame contains theselected sub-channel index. The STA selects a sub-channel based on thesounding frames and sends an RTS on the selected sub-channel. The RTSsets the NAV of the other STAs on the selected sub-channel.

After transmitting the RTS on the selected sub-channel, the STA opensits RX chain only for the selected sub-channel. The AP replies with aCTS on the selected sub-channel. And the AP opens its Rx chain only forthe selected sub-channel. Thereafter, the AP and the STA may exchangeData frames and ACK frames on the selected sub-channel and theunselected sub-channels can be used by OBSS STAs after the end of thetransmission of the RTS frame by the STA.

FIG. 4C depicts a flowchart 400 of a sub-channel hopping embodiment. Theflowchart 450 begins with the AP transmitting a beacon each beaconinterval on a primary sub-channel comprising a hopping schedule for theAP (element 455). The hopping schedule may detail the time slots inwhich or slot boundaries at which the AP cycles through N sub-channelsperiodically. Hopping schedules of OBSSs may be coordinated to betterutilize sub-channels.

A sounding period may follow a beacon or beacons can be used as soundingpackets (element 465). For instance, in some embodiments, rather thanpresenting a sounding period, beacon transmissions may be repeated oneach sub-channel during a beacon interval. In other embodiments, thesounding period may be allocated and the AP may transmit soundingpackets on all the sub-channels. In further embodiments, the AP may bothtransmit the sounding packets during the sounding period and transmitbeacons on each of the sub-channels during the beacon interval.

In response to receiving the sounding packets and/or one or more beaconson one or more of the sub-channels, the STA selects a sub-channel(element 465). For instance, in response to receiving the soundingpackets and/or one or more of the beacons, a STA estimates channelquality of each sub-channel during the sounding period or based on thebeacons. When using beacons for channel estimation, the STA maydetermines that the channel quality is good enough to use, i.e., meetscertain minimum quality criteria for communications such as bit errorrates, based on the received beacon on the sub-channel. If the STAdecides that the channel quality is good enough, e.g., meets one or moreparticular quality standards, the STA may decide to stay on thatsub-channel and access the channel. Otherwise, the STA may move on tothe next sub-channel on which the AP is scheduled to stay for a timeduration.

The STA may access or communicate via the sub-channel when the AP is onthat sub-channel (element 475). In further embodiments, the AP mayadjust time durations associated with each of the time slots duringwhich the AP remains on a sub-channel based on the traffic loadsassociated with the sub-channels. For instance, if a first sub-channelrepeatedly has a higher traffic load than the other sub-channels, the APmay increase the time duration of the time slot of the beacon intervalallocated for the first sub-channel and decrease the time duration ofthe time slots for one or more of the other sub-channels that have lesstraffic.

The following examples pertain to further embodiments. One examplecomprises a method. The method may involve transmitting packets, by anaccess point during a beacon interval, wirelessly on sub-channels of awide bandwidth channel; receiving a selection of a selected sub-channelfrom a communications device; and communicating with the communicationsdevice via the sub-channel.

In some embodiments, the method may further comprise transmitting abeacon to communicate a hopping schedule to the communications deviceduring the beacon interval. In some embodiments, the method may furthercomprise transmitting a beacon to communicate a time slot assignment tothe communications device during the beacon interval. In manyembodiments, the method may further comprise transmitting a managementframe to communicate a target wake time to the communications device. Inseveral embodiments, transmitting the packets comprises transmittingsounding packets across all of the sub-channels of the wide bandwidthchannel during a sounding period. In some embodiments, transmitting thepackets comprises transmitting synch frames across the sub-channelsduring a sounding period. In some embodiments, transmitting the packetscomprises transmitting the beacons. In some embodiments, receiving aselection comprises receiving a power saving poll or other triggerframe. And, in some embodiments, receiving a selection comprisesreceiving a communication the communications device via the selectedsub-channel.

At least one computer program product for communication of a packet witha frame, the computer program product comprising a computer useablemedium having a computer useable program code embodied therewith, thecomputer useable program code comprising computer useable program codeconfigured to perform operations, the operations to carry out a methodaccording to any one or more or all of embodiments of the methoddescribed above.

At least one system comprising hardware and code may carry out a methodaccording to any one or more or all of embodiments of the methoddescribed above.

Another example comprises an apparatus. The apparatus may comprise logicto transmit packets, by an access point during a beacon interval,wirelessly on sub-channels of a wide bandwidth channel; receive aselection of a selected sub-channel from a communications device; andcommunicate with the communications device via the sub-channel; aphysical layer in communication with the logic to transmit the packets.

In some embodiments, the apparatus may further comprise an antenna totransmit and memory coupled with the logic to store frames tocommunicate with the communications device. In some embodiments, thelogic comprises medium access control logic to transmit a beacon tocommunicate a hopping schedule to the communications device during thebeacon interval. In some embodiments, the logic comprises medium accesscontrol logic to transmit a beacon to communicate a time slot assignmentto the communications device during the beacon interval. In someembodiments, logic comprises medium access control logic to transmitsounding packets across the sub-channels of the wide bandwidth channelduring a sounding period. And in some embodiments of the apparatus, thelogic comprises medium access control logic to transmit synch framesacross all of the sub-channels during a sounding period.

Another example comprises a system. The system may logic to transmitpackets, by an access point during a beacon interval, wirelessly onsub-channels of a wide bandwidth channel; receive a selection of aselected sub-channel from a communications device; and communicate withthe communications device via the sub-channel; a physical layer incommunication with the logic to transmit the packets; and an antenna totransmit and memory coupled with the logic to store frames tocommunicate with the communications device.

Another example comprises a program product. The program product forfrequency selective transmission may comprise a storage mediumcomprising instructions to be executed by a processor-based device,wherein the instructions, when executed by the processor-based device,perform operations, the operations comprising: transmitting packets, byan access point during a beacon interval, wirelessly on sub-channels ofa wide bandwidth channel; receiving a selection of a selectedsub-channel from a communications device; and communicating with thecommunications device via the sub-channel.

Another example comprises a method. The method may involve receiving, bya communications device, packets wirelessly on sub-channels of a widebandwidth channel; determining a selected sub-channel by thecommunications device; and communicating with the receivingcommunications device via the selected sub-channel.

In some embodiments, the method may further comprise receiving a beaconcomprising a hopping schedule for an access point during the beaconinterval. In some embodiments, the method may further comprise receivinga beacon comprising a time slot assignment for the communications deviceduring the beacon interval. In many embodiments, the method may furthercomprise receiving a management frame comprising a target wake time forthe communications device. In several embodiments, receiving the packetscomprises receiving sounding packets across all of the sub-channelsduring a sounding period of the beacon interval. In some embodiments,receiving the packets comprises receiving synch frames across thesub-channels during a sounding period of the beacon interval. In someembodiments, receiving the packets comprises receiving beacons on thesub-channels. And, in some embodiments, communicating with the receivingcommunications device via the selected sub-channel comprisestransmitting a PS-Poll or trigger frame to the access point to selectthe selected sub-channel.

At least one computer program product for frequency selectivetransmission, the computer program product comprising a computer useablemedium having a computer useable program code embodied therewith, thecomputer useable program code comprising computer useable program codeconfigured to perform operations, the operations to carry out a methodaccording to any one or more or all of embodiments of the methoddescribed above.

At least one system comprising hardware and code may carry out a methodaccording to any one or more or all of embodiments of the methoddescribed above.

Another example comprises an apparatus. The apparatus may comprise logicto receive packets wirelessly from an access point on sub-channels of awide bandwidth channel; determine a selected sub-channel to communicatewith the access point; and communicate with the access point via theselected sub-channel; and a physical layer in communication with thelogic to receive the packets.

In some embodiments, the apparatus may further comprise an antennacoupled with the physical layer logic to transmit the communication,wherein the logic comprises medium access control logic to receive abeacon comprising a time slot assignment from the access point duringthe beacon interval. In some embodiments, the logic comprises mediumaccess control logic to transmit a beacon comprising a hopping schedulefrom the access point during the beacon interval.

Another example comprises a system. The system may comprise logic toreceive packets wirelessly from an access point on sub-channels of awide bandwidth channel; determine a selected sub-channel to communicatewith the access point; and communicate with the access point via theselected sub-channel; and a physical layer in communication with thelogic to receive the packets; and an antenna coupled with memory.

Another example comprises a program product. The program product forfrequency selective transmission may comprise a storage mediumcomprising instructions to be executed by a processor-based device,wherein the instructions, when executed by the processor-based device,perform operations, the operations comprising: receiving, by acommunications device, packets wirelessly on sub-channels of a widebandwidth channel; determining a selected sub-channel by thecommunications device; and communicating with the receivingcommunications device via the selected sub-channel.

In some embodiments of the program product, the operations furthercomprise receiving a beacon comprising a hopping schedule for an accesspoint during the beacon interval. And in some embodiments, theoperations further comprise receiving a beacon comprising a time slotassignment for the communications device during the beacon interval.

In some embodiments, some or all of the features described above and inthe claims may be implemented in one embodiment. For instance,alternative features may be implemented as alternatives in an embodimentalong with logic or selectable preference to determine which alternativeto implement. Some embodiments with features that are not mutuallyexclusive may also include logic or a selectable preference to activateor deactivate one or more of the features. For instance, some featuresmay be selected at the time of manufacture by including or removing acircuit pathway or transistor. Further features may be selected at thetime of deployment or after deployment via logic or a selectablepreference such as a dipswitch or the like. A user after via aselectable preference such as a software preference, an e-fuse, or thelike may select still further features.

A number of embodiments may have one or more advantageous effects. Forinstance, some embodiments may offer reduced MAC header sizes withrespect to standard MAC header sizes. Further embodiments may includeone or more advantageous effects such as smaller packet sizes for moreefficient transmission, lower power consumption due to less data trafficon both the transmitter and receiver sides of communications, lesstraffic conflicts, less latency awaiting transmission or receipt ofpackets, and the like.

Another embodiment is implemented as a program product for implementingsystems, apparatuses, and methods described with reference to FIGS. 1-4.Embodiments can take the form of an entirely hardware embodiment, asoftware embodiment implemented via general purpose hardware such as oneor more processors and memory, or an embodiment containing bothspecific-purpose hardware and software elements. One embodiment isimplemented in software or code, which includes but is not limited tofirmware, resident software, microcode, or other types of executableinstructions.

Furthermore, embodiments can take the form of a computer program productaccessible from a machine-accessible, computer-usable, orcomputer-readable medium providing program code for use by or inconnection with a computer, mobile device, or any other instructionexecution system. For the purposes of this description, amachine-accessible, computer-usable, or computer-readable medium is anyapparatus or article of manufacture that can contain, store,communicate, propagate, or transport the program for use by or inconnection with the instruction execution system or apparatus.

The medium may comprise an electronic, magnetic, optical,electromagnetic, or semiconductor system medium. Examples of amachine-accessible, computer-usable, or computer-readable medium includememory such as volatile memory and non-volatile memory. Memory maycomprise, e.g., a semiconductor or solid-state memory like flash memory,magnetic tape, a removable computer diskette, a random access memory(RAM), a read-only memory (ROM), a rigid magnetic disk, and/or anoptical disk. Current examples of optical disks include compactdisk-read only memory (CD-ROM), compact disk-read/write memory (CD-R/W),digital video disk (DVD)-read only memory (DVD-ROM), DVD-random accessmemory (DVD-RAM), DVD-Recordable memory (DVD-R), and DVD-read/writememory (DVD-R/W).

An instruction execution system suitable for storing and/or executingprogram code may comprise at least one processor coupled directly orindirectly to memory through a system bus. The memory may comprise localmemory employed during actual execution of the code, bulk storage suchas dynamic random access memory (DRAM), and cache memories which providetemporary storage of at least some code in order to reduce the number oftimes code must be retrieved from bulk storage during execution.

Input/output or I/O devices (including but not limited to keyboards,displays, pointing devices, etc.) can be coupled to the instructionexecution system either directly or through intervening I/O controllers.Network adapters may also be coupled to the instruction execution systemto enable the instruction execution system to become coupled to otherinstruction execution systems or remote printers or storage devicesthrough intervening private or public networks. Modem, Bluetooth™,Ethernet, Wi-Fi, and WiDi adapter cards are just a few of the currentlyavailable types of network adapters.

What is claimed is:
 1. An apparatus, comprising: a transceiver; and a station (STA) comprising logic, at least a portion of which is in hardware, the logic to receive a beacon to indicate a schedule for transmission of a set of sounding frames for frequency selective transmission channel estimation in a Wireless Fidelity (Wi-Fi) network, receive the set of sounding frames, select a subchannel based on the received set of sounding frames, and send a power-saving poll (PS-Poll) frame to indicate the selected subchannel.
 2. The apparatus of claim 1, the logic to receive the set of sounding frames in parallel.
 3. The apparatus of claim 1, the logic to receive the set of sounding frames in series.
 4. The apparatus of claim 1, the logic to determine whether to receive the set of sounding frames in series or in parallel based on the beacon.
 5. The apparatus of claim 1, the logic to send the PS-Poll frame over a primary channel of a basic service set (BSS).
 6. The apparatus of claim 5, the logic to send the PS-Poll frame at a lowest modulation and coding scheme (MCS) transmission rate for the BSS.
 7. The apparatus of claim 1, the logic to send the PS-Poll frame over the selected subchannel.
 8. The apparatus of claim 7, the sending of the PS-Poll frame over the selected subchannel indicating the selected subchannel.
 9. The apparatus of claim 1, the logic to send the PS-Poll frame during a reserved access window (RAW) for subchannel selection.
 10. The apparatus of claim 1, the logic to receive a frame over the selected subchannel in response to the PS-Poll frame.
 11. The apparatus of claim 1, the logic to send a frame over the selected subchannel during a time allocated for data exchange.
 12. The apparatus of claim 1, the logic to receive the set of sounding frames during a time slot reserved for transmission of the sounding frames.
 13. The apparatus of claim 1, the logic to receive beacons over more than one subchannel in series.
 14. The apparatus of claim 1, the beacon to indicate a frequency hopping schedule of an access point (AP).
 15. The apparatus of claim 1, the logic to receive the set of sounding frames at a target wake time (TWT) for the STA.
 16. The apparatus of claim 1, the selected subchannel comprising a 1 MHz, 2 MHz, 4 MHz, or 8 MHz subchannel.
 17. The apparatus of claim 1, the logic to select the selected subchannel from among a plurality of subchannels of a 4 MHz, 8 MHz, or 16 MHz bandwidth.
 18. The apparatus of claim 1, comprising: a memory; and at least one radio.
 19. The apparatus of claim 18, comprising at least one antenna.
 20. An apparatus, comprising: a transceiver; and an access point (AP) comprising logic, at least a portion of which is in hardware, the logic to send a beacon to indicate a schedule for transmission of a set of sounding frames for frequency selective transmission channel estimation in a Wireless Fidelity (Wi-Fi) network, send the set of sounding frames according to the schedule, and receive a subchannel selection in response to the set of sounding frames, the subchannel selection to indicate a selected subchannel for a station (STA).
 21. The apparatus of claim 20, the logic to send the set of sounding frames in parallel.
 22. The apparatus of claim 20, the logic to send the set of sounding frames in series.
 23. The apparatus of claim 20, the logic to allocate a reserved access window (RAW) for receipt of the subchannel selection.
 24. The apparatus of claim 20, the subchannel selection comprising a power-saving poll (PS-Poll) frame.
 25. The apparatus of claim 20, the logic to identify the selected subchannel as a subchannel over which the subchannel selection is received.
 26. The apparatus of claim 20, the logic to receive the subchannel selection over a primary channel of a basic service set (BSS) of the AP.
 27. The apparatus of claim 26, the logic to receive the subchannel selection at a lowest modulation and coding scheme (MCS) transmission rate for the BSS.
 28. The apparatus of claim 20, the logic to reserve a time slot for transmission of the set of sounding frames.
 29. The apparatus of claim 20, the logic to send a frame over the selected subchannel.
 30. The apparatus of claim 20, the logic to send beacons on more than one channel in parallel.
 31. The apparatus of claim 20, the logic to send beacons on more than one channel in series.
 32. The apparatus of claim 20, the beacon to indicate a frequency hopping schedule for the AP.
 33. The apparatus of claim 20, the logic to send the set of sounding frames at a target wake time (TWT) for the STA.
 34. The apparatus of claim 33, the logic to reserve the selected subchannel using a network allocation vector (NAV).
 35. The apparatus of claim 20, the sounding frames comprising clear-to-send (CTS) frames.
 36. The apparatus of claim 20, the selected subchannel comprising a 1 MHz, 2 MHz, 4 MHz, or 8 MHz subchannel.
 37. The apparatus of claim 20, the selected subchannel comprising one of a plurality of subchannels of a 4 MHz, 8 MHz, or 16 MHz operating bandwidth of the AP.
 38. The apparatus of claim 20, comprising: a memory; and at least one radio.
 39. The apparatus of claim 38, comprising at least one antenna. 